The technical field of the invention is that of motor safety and more especially that of safety systems employed in motor vehicles for damping the displacement of certain parts which have been set in motion during a mechanical collision between the motor vehicle and an external object. In fact, during an impact, certain parts of a motor vehicle can constitute a fixed stop for an occupant of a motor vehicle or a pedestrian and thus be liable to injure the occupant or the pedestrian.
Energy absorption devices have already formed the subject of several patent applications.
For example, mention may be made of Patent Application EP 0 550 321, which relates to a pyrotechnic actuator with damped travel that can be used in any type of energy absorption system. This actuator comprises a pyrotechnic gas generator, a piston, a combustion chamber for pyrotechnic substances and a back-pressure chamber, and also an intermediate chamber included between the combustion chamber and one end of the piston. A channel connects the intermediate chamber to the back-pressure chamber. The gas emitted by the generator pressurizes the intermediate chamber in order to oppose the movement of the piston and thus damp its travel, some of the gas being conveyed through the channel towards the back-pressure chamber.